The oxidation of ascorbic acid and hydroquinone by perhydroxyl radicals. A flash photolysis study

Nadezhdin, A. D.; Dunford, H. Brian

doi:10.1139/v79-491

Cited by 47 publications

(15 citation statements)

References 5 publications

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“…, is directly involved in this catalytic reaction. The partial inhibition, however, suggests that superoxide radical anions are produced during this reaction, and they play a role in ascorbate degradation, probably via the superoxidescavenging reaction by ascorbate (31)(32)(33)(34). Together these results indicate that MG-BSA behaves as an enzyme, which has an ability to catalyze the oxidation of ascorbate in the presence of oxygen to produce superoxide radical anion and semi-dehydroascorbate radical.…”

Section: Resultsmentioning

confidence: 92%

Oxidation-Reduction Properties of Methylglyoxal-modified Protein in Relation to Free Radical Generation

Lee¹,

Yim²,

Chock³

et al. 1998

Journal of Biological Chemistry

146

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Glycation reaction (nonenzymatic glycosylation; Maillard reaction), which produces brown fluorescent compounds, is a chance event that may occur when a protein is in solution with a reducing sugar, such as glucose. In this reaction, free amino groups of protein react slowly with the carbonyl groups of reducing sugars to yield Schiff-base intermediates, which undergo Amadori rearrangement to stable ketoamine derivatives (1). These Amadori products subsequently degrade into ␣-dicarbonyl compounds, deoxyglucosones (2). Schiff bases can also be fragmented to glyoxal (3). These compounds are more reactive than the parent sugars with respect to their ability to react with amino groups of proteins. Thus, the ␣-dicarbonyl compounds or ␣-ketoaldehydes are mainly responsible for forming inter-and intramolecular cross-links of proteins, known as advanced glycation end products (AGEs) 1 (1). The AGEs, which are irreversibly formed, accumulate with aging, atherosclerosis, and diabetes mellitus, especially associated with long-lived proteins such as collagens, lens crystallins, and nerve proteins (4 -8).The ␣-dicarbonyl compounds are produced in a variety of ways. Fenton reaction-mediated oxidation of sugars, lipids, and proteins produces various ␣-dicarbonyl compounds. Accordingly, the transition metal ion-catalyzed oxidation of glucose is suggested to be a more important factor in glycation than the formation of the Amadori product of glucose itself (9 -11). The ␣-ketoaldehydes, such as methylglyoxal, are also found as a normal metabolite in mammals and microorganisms. The methylglyoxal is formed by the non-enzymatic or enzymatic elimination of phosphate from triose phosphate and by the oxidation of hydroxyacetone and aminoacetone (12-14). The increased formation of methylglyoxal was observed in hyperglycemia associated with diabetes mellitus (15, 16). In addition, it was shown that methylglyoxal-modified albumin underwent receptor-mediated endocytosis by macrophage, which may suggest the involvement of methylglyoxal in pathophysiology (17). Also, it was suggested that cellular oxidant stress or free radicals are generated by AGEs themselves (18,19) or as a consequence of the AGEs interaction with their receptors (20,21).Several AGEs were identified from the products formed during the reaction of methylglyoxal with model compounds and proteins. These species include N ⑀ -(carboxyethyl)lysine (22), imidazolone compounds (23), and imidazolium cross-link species, methylglyoxal-lysine dimer (24 -26). In addition to these AGEs, several investigations have also shown by electron paramagnetic resonance (EPR) spectroscopy that unidentified protein free radicals were produced during the reaction of methylglyoxal with proteins, such as bovine serum albumin (BSA) and casein (27,28). In our previous report (29), the free radical was assigned to be the radical cation of the cross-linked Schiff base on the basis of the detailed analysis of EPR spectra observed from the reaction mixture containing methylglyoxal and alanine. We also sugges...

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Section: Resultsmentioning

confidence: 92%

Oxidation-Reduction Properties of Methylglyoxal-modified Protein in Relation to Free Radical Generation

Lee¹,

Yim²,

Chock³

et al. 1998

Journal of Biological Chemistry

146

View full text Add to dashboard Cite

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“…It has been suggested that the superoxide radical 02 may be an intermediate in this II reaction [25]; however, the absence of 02 in oxygenated neutral or alkaline solutions of H2A [25] implies the oxidation step is a single two electron process. H2A has also been shown to undergo a redox reaction with 02 ~ [64,65]. Since H2A is a fairly strong acid it may be expected that this molecule would induce the disproportionation of 02 to H202 and molecular oxygen.…”

Section: The Autoxidation Of Ascorbic Acidmentioning

confidence: 99%

Contributions of electron spin resonance spectroscopy to the study of vitamins C, E and K

Craw

Depew

1985

Res Chem Intermed

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“…The reducing power of AA also endows it with substantial antioxidant properties. Thus, AA recycles vitamin E back into its antioxidant form (Packer et al, 1979) and quenches active oxygen species, i.e., -OH, 0 2 * and l02, which arise as byproducts of single electron transport reactions (Fessenden and Verman, 1978;Bodaness and Chan, 1979;Nadezhdin and Dunford, 1979).…”

mentioning

confidence: 99%

Loss of Ascorbic Acid from Injured Feline Spinal Cord

Pietronigro

Hovsepian

Demopoulos

et al. 1983

Journal of Neurochemistry

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Feline spinal cord contains 0.97 mM ascorbic acid, as measured by the dinitrophenylhydrazine method. Greater than 90% is maintained in the reduced form. When functioning normally, the CNS conserves its ascorbic acid with a turnover rate of 2% per h. Following contusion injury severe enough to produce paraplegia, ascorbic acid is rapidly lost from injured spinal tissue. Thus, ascorbic acid is decreased 30% by 1 h and 50% by 3 h following injury. Oxidized ascorbic acid is increased at 1, but not 3, h following impact. As a consequence of its many functions in CNS, loss of ascorbic acid may contribute to derangements in spinal cord function following injury.

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The oxidation of ascorbic acid and hydroquinone by perhydroxyl radicals. A flash photolysis study

Cited by 47 publications

References 5 publications

Oxidation-Reduction Properties of Methylglyoxal-modified Protein in Relation to Free Radical Generation

Oxidation-Reduction Properties of Methylglyoxal-modified Protein in Relation to Free Radical Generation

Contributions of electron spin resonance spectroscopy to the study of vitamins C, E and K

Loss of Ascorbic Acid from Injured Feline Spinal Cord

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